Trouble defining an action--

I am absolutely puzzled about why the following is returning problem messages for both of the rules–

Knocking on it is an action applying to one visible thing and requiring light. Understand "knock on [something]" as knocking on it. Check knocking on something: if the noun is not the red front door: instead say "I doubt you'll get the answer that you want." After knocking on the red front door: say "You are answered by an insolent silence."

Is it because of the placing of the preposition in the name of the action? The problem message is the usual ‘doesn’t make sense as the definition of an action’ and ‘therefore I can’t place it into a rule book’ kind of thing. I thought I had clearly defined the action…??
If it’s the preposition, maybe I can change the ‘knocking on’ to simply ‘knocking’ and use an Understand to allow ‘knock on’…??

I think your problem has to do with the use of “it”. The following should work:

Knocking on is an action applying to one visible thing and requiring light. Understand "knock on [something]" as knocking on. Check knocking on something: if the noun is not the red front door: instead say "I doubt you'll get the answer that you want." After knocking on the red front door: say "You are answered by an insolent silence."

I think “it” is just used for actions that take two nouns (i.e. putting it in), so for actions that take only one noun, replacing “it” with a noun won’t work, as far as I can tell.

Thanks Brian–I’m sure you’re right–earlier I had created a verb ‘examining it through’(which did require two nouns, the object being examined and another noun through which you would look–ideally the binoculars, otherwise you would get a humorous response) and referred to it for some clue as to why ‘knocking on it’ did not work. My other verbs, which did not require two nouns, I did not include an ‘it’–with ‘knocking on’, I thought it would, because there’s a preposition(like ‘through’). They worked, but ‘knocking on it’ would not. Thanks.
Instead I settled on ‘knocking’ along with an ‘understand’ assertion to allow ‘knock on’. I like it because it works with any noun–my response is ‘You deal [the noun] a punishing blow, but it hardly moves.’